Desaturate colors around lightsource
To desaturate objects closer to a light, add 4 nodes to your object's material:

Texture coordinate &gt; Object: target your light
Vector Math &gt; Length - gives lower value for objects closer to that light
Math &gt; Multiply - to control the falloff
Hue/Saturation node, to control the saturation

(You can wrap the setup in a nodegroup and put inside every material)